Laminated plastic removable insole



Jan. 17, 1950 R. 1 WOODBURY Er Al.

LAMINATED PLASTIC REMOVABLE INsoLE Filed Dec. 8, 1942 page INV ToRf oodmty 4,

, Ml p jffoR/vey Patented Jan. 17, 1950 LAMINATED PLASTIC REMUWABLEINSLE Robert L. Woodbury, United States-Army, Litchfield, Conn., andEarl P. Hanson, Long Island City, N. Y.

Appiicaticn December 8, 1942, Serial No. 463,192

(El. SG--MJ (stratified under the met of March 3, i883, as amended April30, i928; 37?@ fl. G. "157) 6 Claims.

The invention described herein, if patented, may be manufactured andused by or for the Government for governmental purposes, Without thepaymentto us of any royalty thereon.

The present invention relates to footwear, and more specifically to aremovable insole adapted to be placed in any conventional type of shoeto provide greater comfort, aid in overcoming effects of excessiveperspiration, make possible more effective control of foot infections,and to provide a more sanitary, more comfortable and generally moredesirable insole than heretobefore lfnown or used.

The prime object of the present invention resides in the provision of aremovable shoe insole comprising one or more layers of open weave, wovenplastic fabric, the fabric being of the mono-filament type and of aplastic composition impervious to the effects of perspiration, so thatalthough the individual strands of the fabric are entirely non-porousand non-absorbent, the open weave will permit unrestricted drainage andample ventilation.

A further object of the invention resides in the provision of aremovable shoe insole consisting of a plurality of layers of plasticfabric, the plastic being of a substantially non-hygroscopiccomposition, unaifected appreciably by temperatures in the range of 212F. and of flexible mechanical characteristics, so that the insole may becleansed and disinfected by boiling, without materially damaging thestructure of the insole or altering the chemical composition of theplastic.

A further object of the invention resides in the provision of aremovable insole of mono-filament plastic fabric adapted to retainreasonably its resilient characteristics and maintain an eiective airspace between the foot of the wearer and the sole of the shoe toinsulate the foot and provide greater comfort to the wearer underconditions of extremely high temperatures; as for example, combatconditions in tropical or desert cui l do not tend to accumulate.

These and other objects are accomplished in the present invention by theprovision of an insole structure including one or more layers of openmesh fabric wherein the individual strands of the fabric are composed ofa plastic composition that is insoluble and non-absorbent. Further, thepresent invention makes use of a mono-filament fabric; that is, a fabricwherein each individual strand is continuous, solid, resilient,non-porous, and non-absorbent, as distinguished from a thread made up ofa multiplicity of relatively short hygroscopic strands of fibers.

The use of the mono-filament plastic fabric accomplishes certainunobvious and very desirable results in the reduction of foot infectionsand increase in foot comfort, for several reasons.

First, the individual strands of the fabric layers retain their springyresilient qualities even when the shoe is worn under conditions ofextreme heat and humidity sumcient to cause excessive perspiration.Under such conditions, it is well known that any ordinary fabric becomesthoroughly soaked with moisture and matted into a soggy pad. havinglittle or no cushioning effect, and entirely impervious to thecirculation of air. In contrast, an insole manufactured according to theteachings of this disclosure'retains its full normal thickness andresiliency, since theindividual strands of the fabric absorb nomoisture.

Further, since the mono-filament plastic fabric exhibits no tendency toflatten or mat, the interstices between the individual strands of thefabric are at all times open and unobstructed. This characteristicserves a dual function in that it provides full unobstructed drainagethrough the insole and since it permits a free and constant circulationof air throughout and between the individual insole layers, thusproviding effective ventilation for the foot.

In addition, the characteristic of maintaining this air space within theinsole provides a sufficient thermal insulating layer so that the shoemay be worn under excessively high temperature conditions without greatdiscomfort.

3 Referring now more particularly to the drawing attached to and forminga part of the present specification:

Figure 1 is a plan view of an insole constructed in accordance with theteachings of this disclo-l sure.

Figure 2 is an enlarged detail sectional view taken substantially on theplane of the line 2-2 of Figure 1.

Figure 3 is an enlarged detail sectional view similar to Figure 3 andillustrating a modified form of edge binding for the insole.

The insole, generally indicated at I0, consists of a plurality of layersof fabric II, I2, I3, Il, and I5, formed to correspond with the shape ofthe inside of a shoe and bound together around their marginal edges. Asillustrated in I and `i! of the drawings, the individual layers offabric are united by a binding strip I8 stitched to the fabric layers bya line of stitches Il.

Any one of several types of binding may be used for the purpose, itbeing contemplated that the binding strip I6 may be of plastic,composition, rubber, fabric, leather, or any other flexible materialhaving satisfactory wearing qualities. Further, the invention is notregarded as limited to a stitched edge binding and it is contemplatedthat the several layers of plastic fabric may be brought together at theedges and sealed by fusing the individual layers of the plastic togetherat the extreme edge, to form a fused binding I8 as illustrated in Figure3, or by cementlng.

The novelty of the present invention resides particularly in theprovision of a removable insole wherein the individual layers of fabricare composed of an insoluble and non-absorbent open mesh plastic fabricof the mono-filament type, having each individual thread of the fabriclformed of 'an extruded, solid, non-porous, and

non-absorbent' filament of plastic material.

It is contemplated that satisfactory results may be obtained by such amono-illament plastic fabric in any one of a wide range of mesh gaugesand strand sizes, but highly satisfactory results have been obtained bythe use of a fabric of square mesh, sixteen or eighteen strands to theinch, and having an individual strand diameter of .016 inch.Satisfactory results have also been obtained by the use of a square meshfabric of twenty-four strands to the inch, wherein the individualstrands have a diameter of .0125 inch. It is to be noted, however, thateach of these fabrics is of the open weave type, having the spacesbetween the individual strands wider than the diameter of the strands,so that air may circulate freely through the fabric.

Further, it is believed that any one of a number of commercially knownplastics may be successfully used, though it may be stated that entirelysatisfactory results have been obtained by the use of a copolymer vinylester (e. g. vinyl chloride) and vinylidene chloride plastic of the typedescribed in U. S. Patent No. 2,160,931 and produced commercially by theDow Chemical Company under the name of Saranl It is also contemplated tobe within the scope of this invention to use any number of layers offabric having the same or different mesh gauges and any possiblecombination of fine mesh and coarse mesh fabrics, but it is foundadvantageous under certain circumstances to provide a relatively finemesh fabric II on the upper surface of the insole and a plurality oflayers of abutting coarser mesh I 1 I3, I4 and I5 below the fabric II tospace it above the sole of the shoe. When 4 so constructed, satisfactoryresults have been obtained by the use of plastic fabric of a mesh of 24)strands to the inch for the upper layer and a plastic fabric of 16 to 18strands to the inch for the lower layers I 2, I3, I4, and I5.

It will be readily understood that when the liner fabric is used on theupper surface of the insole, any particles of dirt, sand or otherforeign matter that may work through the finer fabric will easily passthrough the coarser lower layers of fabric. Thus the dirt willeventually be discharged through the lower layer of fabric, and theporosity of the insole will not be apt to be lessened by excessiveaccumulation of dirt.

Further, it may be pointed out thatsince the chemical composition of theplastic utilized is such that it will not soften excessively in hightemperature, the insole may be cleansed and sterilized by boiling. R f

It is also contemplated that, if desired, beneilcial results may beobtained by inserting a medicated fabric layer between the layers offabric heretofore described, so that the medicament will be graduallydissolved or disseminated by means of heat and perspiration incident touse asthe insole is worn,'to provide a constant antiseptic tending tomaintain the insole in a completely sterile condition at all times.Paraformaldehyde, trioxymethylene and menthol, with or without theaddition of boric acid, are possible medicaments, though vother suitablesubstances may be employed. A` medicated pad as thus de'- scribed may beof any size and shape, though it is contemplated that it will probablybe most satisi'a'ctory in the general conguration indicated at I9 in thedrawings, spaced and located to provide medicament in the vicinity ofthe toes of the shoe. a

From the foregoing, it will be apparent that the practice of the presentinvention will result in an insole structure having properties notheretofore known in the art. Further, it is submitted that the newproperties represent a substantial contribution to the art to which theinvention relates, in that the result in a more comfortable device thanheretofore known, as well as in a device that is more sanitary, moreeffective as an insulator, more easily cleaned, and capable of providingmore effective drainage and ventilation.

In conclusion, it is believed pertinent to point out that the presentpreferred embodiment of the invention illustrated in this applicationhas been developed with the view toward meeting present militaryrequirements, but that the invention is believed to have great value incivilian and commercial fields as well. It is therefore requested thatthe scope of the inventive thought of this application be regarded aslimited only by the terms of the appended claims.

Having thus described our invention, what we claim as new and desire tosecure by United States Letters Patent is:

1. A shoe insole comprising a plurality of layers of open weave plasticfabric superimposed upon one another; each of the fabric layersconsisting of a multiplicity of solid, resilient, nonporous,non-hygroscopic, extruded strands of temperature resistant, flexibleplastic; the strands being woven together into an open mesh fabrichaving the interstices between the individual strands Wider than thediameter of the individual strands: all of the fabric layers being cutto a size and shape approximately the size and shape of a human foot andall of the layers being fused ether around their marginal edges.

4. An inner sole for a shoe or the like compris# ing a plurality ofwoven webs of thermoplastic threads having a welded joint about itsperiphery, the said inner sole when free of load being convex incross-section and having a.` greater thickness within the weldedvperipheral joint than at the welded peripheral Joint.

5. A .plastic inner sole comprising a plurality of superimposed layersof inner sole shapes fused together along the edges, said layerscomprising relatively coarse intermediate layers and a ne outer layer.

6. A plastic inner sole comprising a. plurality of es superimposed wovenlayers of inner sole shapes fused together along the edges. said layerscomprising relatively coarse intermediate layers and a iine outer layer.and a medicated pad positioned between two of said woven layers.

ROBERT L. WOODBURY. EARL P. HANSON.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,106,986 Stucki Aug. 11, 19142,121,604 Lynch June 21, 1938 2,183,602 Wiley Dec. 19, 1939 2,244,844Margel June 10, 1941 2,312,089 Gobeille Feb. 23, 1943 FOREIGN PATENTSNumber Country Date,l

25,781 Great Britain 1903 540,521 Germany Jan. 28, 1932

